Can this anonymous email be traced back to me?

Question

I used TOR browser and guerillamail to send an email anonymously (or so I think).

Is there any way this can come back to me? I used my own laptop on my home wifi network. I just opened Tor, did some googling about how to send an anonymous email and found guerillamail and sent it through that. I have confirmed the EXIF data doesn't have anything important, and plus the picture has been cycled through multiple phones by now.

Anyways, I don't really know how anonymous Tor is, so I am asking here. If they get their hands on server logs from my ISP, would they be able to see my Tor activity? Would they only be able to see me using Tor or the exact sites/browsing I did? Lastly, would they be able to get the MAC address of my laptop or something other piece of info that would surely prove it was me?

Answer 1

They can't trace you (for official statement) even if you didn't use Tor for that, but some anonymous email service that does not require phone number (there are plenty of them) outside your jurisdiction.

With Tor, they can't even suspect you because "you used that mail server in that time message was sent". Without Tor they can.

No, Tor traffic is onion encrypted and goes through number of random relays. You were absolutely anonymous for the mail service you used as long as you didn't enter your personal data there.

Answer 2

Okay I'm taking this account briefly out of retirement because Croll's answer is wrong and massively misleading.

Yes, they can (most likely) figure out that it was you, technologically at least.

So the scenario is that you sent an email from some mail server to a group that only you and your classmates know about. Straight away you've acted within a small subset of possible candidates.

1. From either the mail headers or a subpoena, they can discover that the email was sent over Tor.

2. From either the mail headers or a subpoena, they can discover when the email was sent.

3. From the small set of possible candidates, how many of them were connecting to Tor at the time the email was sent? I'm guessing the answer is ~1 (you).

There is precedent for this in the case of the Harvard "Bomb Threat" Hoax who, in 2013, made exactly the same mistake that you have.

The issue is that you created a very small anonymity set, you take a few sets of people: The people who know your friend, the people who know the recipient email address, the people online at the time the email was sent, the people on Tor at the time the email was sent. Now take all these sets and put them on a Venn Diagram. Where all these sets overlap is a very small area, probably consisting of just you.

Now, here's where you might not get caught. Local police departments aren't technologically sophisticated and they don't have a lot of time to devote to it. They'd likely need some kind of warrant or subpoena for all the users internet connection records, I'm not a lawyer so I don't know how plausible that would be in your jurisdiction. If you are already of particular interest to the investigation such that they can show probable cause or reasonable suspicion, then you're going to be getting asked some questions by law enforcement.

Note: It may be noteworthy that the Harvard Student confessed when the FBI questioned him, we didn't get to see this play out in court, so how well he might have been able to maintain plausible-deniability was not tested. But in general what you are doing is not safe or anonymous and there's no technical reason you wouldn't be caught.